package iD220711010131;

import java.util.Scanner;

public class HuangJiaLe09 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while(sc.hasNext()) {
            double radius = sc.nextDouble();
            System.out.printf("%.3f", round(radius));
            System.out.println();
            
        }
    }public static double round(double radius) {
        double round = radius * radius * radius * 3.1415927 * 4 / 3;
        return round;
    }
}
